Which of the Following Methods Use Microbial Biofilms for Secondary

Question

Which of the following methods use microbial biofilms for secondary phase of wastewater treatment?
A)trickling filter
B)activated sludge
C)anaerobic digester
D)nitrification tank
E)oxidation pond

Accepted Answer

Trickling filters use microbial biofilms to treat wastewater during the secondary phase of treatment. The filters contain a stationary bed of rocks or plastic media over which the wastewater flows, allowing for the development of biofilms that break down organic matter in the wastewater. Activated sludge, anaerobic digesters, nitrification tanks, and oxidation ponds all use different methods for the secondary phase of wastewater treatment.